GENERAL DISTRIBUTION:
Spreading dogbane is widely distributed throughout North America. It occurs in every U.S.
state except Hawaii, Kansas, and the southeastern states of Louisiana, Mississippi, Florida,
and South Carolina [182]. Spreading dogbane can be found in most Canadian provinces [74] and
occurs in Mexico [137]. A. a. var. incanum can be found scattered throughout Nova
Scotia [137] and A. a. var. pumilum is found in west-central Montana [98].
Intermediate dogbane is found primarily in areas where spreading dogbane and Indian hemp habitats
overlap [137,189,190,191]. Plants database provides a
distributional map for spreading dogbane.

HABITAT TYPES AND PLANT COMMUNITIES:
Spreading dogbane is common in dry, open areas and is often found after a disturbance.
It is recognized as dominant or codominant in the Rocky Mountain Douglas-fir
(Pseudotsuga menziesii var. glauca)/white spirea (Spiraea betulifolia)
habitat type of central Idaho [160] and as dominant in old jack pine (Pinus banksiana)
stands in the boreal forests of Saskatchewan [112].

Spreading dogbane is a native perennial that can grow to 40 inches (100 cm) in height [39].
Stems are erect and diffusely branched, glabrous, and lack a central axis [73,86,98,116,191].
Leaves are opposite, spreading or drooping, glabrous above and pubescent beneath. Leaf size
ranges from 0.4 to 5 inches (1-12 cm) in length and 0.2 to 2 inches (0.5-6 cm) in width [64,81,98,189,190,191].

The flowers of spreading dogbane are erect or nodding and small, 0.2 to 0.3 inch (6-8 mm) long
[127,147]. The corolla is typically 0.2 to 0.5 inch (4-12 mm) long, broadly campanulate, and
approximately 3 times the length of the calyx [61,64]. Spreading dogbane follicles are 1.6 to 6
inches (4-15 cm) long and pendulous or erect when mature [116,191]. Epidermal hair around the head
of the stigma ensures that pollen is not lost [56]. Seeds are numerous, 2 to 3 mm long with a 0.4
to 0.8 inch (1-2 cm) long coma [60,64,70].

Spreading dogbane has rhizomes that have been detected to depths of greater than 10 inches (25 cm)
and are located primarily in mineral soil [195].

Intermediate dogbane can grow to 40 inches (100 cm) in height [98]. It produces progeny with low
pollen fertility [39] and can appear identical to either of the parent species, spreading dogbane or
Indian hemp [6].

The inflorescence of A. a. var. pumilum is often larger and the corolla more tubular
than that of spreading dogbane
[74].

Pollination:
Spreading dogbane is insect and self-pollinated [83]. Insects transfer pollen from the anther to
the stigma upon withdrawal of the proboscis. Cross-pollination occurs when pollen remains adhered
to the proboscis and is transferred to the stigma of another flower [56].

In Colorado, approximately 71 species of insect were recorded visiting spreading dogbane over a
15-hour period. None had detectable amounts of pollen from Apocynum spp. plants [83]. A study
in South Dakota concluded that behavior of 2 bumblebee species was determined by the density of spreading
dogbane plants and availability of alternative food sources [126].

Seed banking:
There is no indication that spreading dogbane stores its seed in soil [158,159,160,161].

Germination:
Germination requirements for spreading dogbane are not well known [161]. Seed collected from
the prairies of Wisconsin in 1946 had 56% germination rates when stratified for 2 months and
36% germination rates when not stratified. The seed was planted in flats and exposed to temperatures
of 65to 70 ºF (18-21 ºC) for 2 months before being stratified outdoors or kept indoors at 40
ºF (4 ºC) for 2 to 3 months [65].

In a study to determine the viability of seeds after submersion in water with temperatures ranging
from 33 to 81 ºF (0.5-27 ºC), most spreading dogbane seeds either germinated and/or deteriorated in
the first 3 months of submersion. Those that remained firm had germination rates ranging from <1%
to 8% following 3 to 24 months of water submersion while germination rates for seed that was not
submerged ranged from 53% to 91%. None of the seeds germinated after 36 or more months of submersion
[33]:

Seedling establishment/growth:
No information is available on this topic.

Asexual regeneration:
Asexual reproduction of spreading dogbane is attained through rhizomatous sprouts
[9,161]. Sprouting from rhizomes has also been observed following disturbance
[29,165].

SITE CHARACTERISTICS:
Spreading dogbane has a broad distribution encompassing a wide variety of site characteristics.
It is most common in dry, open areas [181], but can also be found in riparian zones [106] and
shady, moist areas with clayey soils [92]. Spreading dogbane is located at elevations ranging
from sea level to 11,000 feet (3,400 m) [181] with temperatures ranging from 18 to 90 ºF (-8 to
32 ºC) [1,107], and pH levels of 5.0 to 7.7 [41,88]. Additional site characteristics for spreading
dogbane are provided in the table below:

SUCCESSIONAL STATUS:
Spreading dogbane can occur in various successional stages. It does well in full sun or
partial shade [161] and is considered a representative mid-seral species in multiple
habitat types [158,159,160,161]. Spreading dogbane often provides important cover in
locations with sparse vegetation [199] such as recently disturbed areas [187]. In Indiana,
it was identified along with other forbs and shrubs in the early stage of prairie encroachment
by trees [149]. Spreading dogbane is found in early successional stages on the shores of
Lake MacDonald in northwestern Montana [67] and is considered a "secondary" species
in Michigan aspen (Populus spp.) associations [58].

In Manitoba, wooden screens were placed to allow 25%, 50%, 75%, and 100% shade over plots
which had been fire-pruned, burned with a propane burner resulting in ground temperatures
of 260 to 480 ºF (125-250 ºC)). Spreading dogbane sprouted in plots allowing 75% shade with
10% frequency and 6% cover and did not return to any of the other plots [76], suggesting
shade tolerance in spreading dogbane. Variability in light tolerance may exist across
populations and/or locations.

SEASONAL DEVELOPMENT:
Flowering dates throughout the range of spreading dogbane vary over a 4-month period. Fowler and
Tiedemann [53] found that 1st bloom and peak bloom of spreading dogbane occurred when soil moisture
content of the top 6 inches (15 cm) of soil reached 3% and 5%, respectively. Flowering dates
for spreading dogbane are summarized below:

Flowering dates following 6 years of observation in southeastern North Dakota
were as follows [26]:

Earliest first bloom

Latest first bloom

Median date of full flowering

Median date when 95% of flowering complete

Length of flowering period (days)

9 June

21 June

29 June

22 July

32

Intermediate dogbane flowers from May to August in Arizona [87]. Fruits develop
from September to October in the Carolinas [128].

A. a. var. incanum in northeastern Oregon was in bud the 3rd week
of July, flowering the 4th week, flowering and fruiting the 1st and 2nd weeks of
August, and fruiting the last 2 weeks of August and the 1st week of September
where it occurred with vine maple (Acer circinatum) associations. Within
coast Douglas-fir (Pseudotsuga menziesii var. menziesii)
associations, A. a. var. incanum was in bud the 1st week of August and
flowering the 2nd and 3rd week of August [133].

FIRE ECOLOGY OR ADAPTATIONS:Fire adaptations:
Spreading dogbane recolonizes burned sites immediately after fire through rhizomes
[9,29,51,163,165,166,166]. The position of perennating parts below the soil surface
allows spreading dogbane to survive short (12 to 15 year) fire intervals in boreal forests
[140]. Spreading dogbane may also recolonize a site through seed germination from off-site
seed sources [4], although examples have not been documented.

Fire regimes:
Spreading dogbane is found in communities that experience long and short fire return intervals.
It is most common in dry environments with short fire intervals [9], but has been found among
interior ponderosa pine (Pinus ponderosa var. scopulorum) stands with historic mean
fire return intervals of 20 to 23 years that had not burned in 96 years [197]. Where spreading
dogbane occurs in interior ponderosa pine-Rocky Mountain Douglas-fir habitat types, grazing has
resulted in the promotion of younger, denser stands of even-aged trees that are more susceptible
to disease and insect outbreaks and consequent increases in high severity fire risks [202].

Where spreading dogbane is found with quaking aspen (Populus tremuloides), the longevity
of stands is dependant upon the time of fire following germination. Short fire intervals
discourage aspen regeneration where extensive root masses have had insufficient time to develop
[58]. Although the effect of fire on spreading dogbane within these associations has not been
reported, it is unlikely that variable fire return intervals would affect its presence. Spreading
dogbane in white fir (Abies concolor) habitat of southern Oregon is able to withstand
periods of 15 years or more without fire and was detected in areas that had not burned in 134
years [108].

The following table provides fire return intervals for plant communities
and ecosystems where spreading dogbane is important. For further information, see
the FEIS review of the dominant species listed below.

PLANT RESPONSE TO FIRE:
Spreading dogbane responds well to fire disturbance [187]. It maintains comparable pre
and postfire frequencies through its ability to sprout from adaptive rhizomes [9,29,51,163,165]. Spreading dogbane has been reported after fall and spring burns [30] and
following low- [78] and high-severity fires [10]. Coverage of spreading dogbane has
been reported to increase with increasing fire intensity in interior ponderosa pine-Douglas-fir forest types in Montana [11].

Reports indicate that spreading dogbane is able to germinate on recently burned soil [171],
likely from off-site seed sources [4]. In the absence of frequent disturbances, populations
of spreading dogbane are reported to die out [9], although populations have been reported
up to 134 years following fire [108].

DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:
Due to its broad distribution, accounts of spreading dogbane following fire are widespread
and vary throughout a range of ecosystems. Adverse postfire effects on spreading dogbane
appear to be temporary with reports of fluctuating population cover and frequency in the
years following fire. A large percentage of studies fail to report the significance of the
increase or decrease of populations, likely due to a lack of prefire data. Where spreading
dogbane occurs, it is commonly found on both burned and unburned sites [9] such as Pacific
ponderosa pine (Pinus ponderosa var. ponderosa)stands in Oregon [141], jack pine stands in northwestern Wisconsin [186],
chestnut oak (Quercus prinus) stands in south-central New York [171], and clearcuts in eastern Ontario [196].

California:
Spreading dogbane has been observed after fires in northern California [93,169]. Following
fire in the hardwood forests of northwestern California, it was reported to have 1.5% and
3.4% mean relative cover on 2 sites [169].

Idaho:
Spreading dogbane cover increased from 0.5% to 0.9% following a shelterwood cut at the
Priest River Experimental Forest in northern Idaho. Areas subsequently treated with a
"moist" burn (duff was moist and fire was conducted 1 day during the warmest,
driest period) had 1.0% cover prior to cutting and burning and 2.6% cover 1 year after
treatment. Areas treated with a "dry" burn (duff was dry and burn was conducted
over the course of 2 days throughout the evening, night, and morning) had 0.5% cover prior
to treatment and 1.4% cover 1 year following cutting and burning [154].

Cover and frequency of spreading dogbane on high intensity prescribed burns in Idaho were
significantly higher (P<0.01) than cover and frequency on control and low intensity burn
sites averaged across the 1st 3 years [10]. Following a large wildfire in a western larch
(Larix occidentalis)-Douglas-fir cover type in northern Idaho, spreading dogbane
constituted a maximum of 10% to 14% of cover within the 1st postfire decade due to vegetative
reproduction [164]. It was reported on 11 of 21 plots measuring 16 × 82 feet (5 × 25 m),
returning 2 to 15 years postfire on sites that had previously supported standing timber or
shrubfields. It was not reported on clearcut sites. Three plots reported flowering in the
1st year [165].

Logging and helicopter yarding were conducted in Rocky Mountain Douglas-fir habitat types of
central Idaho in September through November, 1976. Micro plots on each of the logged areas
were burned under prescription or by wildfire following harvest activities and vegetation
plots were measured 1, 2, 5, and 10 years postburn. A comparison of burned and unburned areas
in the years following fire resulted in the following cover [59]:

Prescribed burned (% cover)

Wildfire burned (% cover)

Year

Unburned

Burned

Unburned

Burned

Pre-disturbance

1

1

1

1

1

1

1

2

1

2

<1

1

1

1

5

1

2

2

3

10

1

2

1

2

Maine:
Five years after a wildfire on Peaks Island off the coast of Maine, spreading dogbane
was considered a characteristic "shrub" layer. The area had also experienced
fire 26 and 28 years prior to measurements [37]. On Mount Desert Island off the coast of
Maine, spreading dogbane returned through vegetative reproduction 1 year after the 1923
wildfire and was considered "abundant" [155].

Michigan: In Michigan spreading dogbane was found on mature jack pine stands, unburned
jack pine stands within a 3-year-old clear cut, and jack pine plots burned under prescription
1 and 2 years previously. The highest frequency of spreading dogbane was found on the 1-year-old
prescribed burn site [1]. In the gray birch-red maple (Betula populifolia-Acer
rubrum) habitat type of Painted Rocks National
Lakeshore, spreading dogbane had an average frequency of 13% and constancy of 9% in an area that
had previously experienced fire [102].

In northern lower Michigan, spreading dogbane populations were assessed at 5 sites supporting
eastern white pine(P. strobus), red pine (P. resinosa) , northern red oak
(Q. rubra), and red maple that had previously experienced natural
and/or prescribed burns. Based on 100 1×1 m² quadrats at each site, spreading dogbane was absent
from 4 sites and found with 1% frequency on 1 site 27 years following fire [143]. Out of 53
recorded years, it showed the greatest frequency 16, 38, 45, and 50 years following fire [144].

Spreading dogbane in mature red pine-eastern white pine stands on the southwestern lower peninsula of Michigan had highest cover (0.96%) on a site that
had experienced 3 biennial burns and was not found on sites that had been burned once or were
unburned. Frequencies obtained from 1 m² plots following various burn treatments are as follows
[117]:

Biennial

Burned once

Unburned

Spreading dogbane frequency

1994 (2 burns)

1995 (3 burns)

1994

1995

1994

1995

0.3

1.9

0.1

0

0

0

Minnesota:
In a study related to burn succession in coniferous forests of Minnesota, spreading
dogbane was found on 7 of 10 burns. It was abundant in the herbaceous stage after a
pine burn [63]. In the boreal forests of northern Minnesota, plots were examined in
order to determine the effects of fire, logging, and forest type on biodiversity.
Spreading dogbane was found on 54.3% of postfire stands and 45.7% of post-logging
stands. Prefire occurrence was not recorded [130].

In northeastern Minnesota, a single spreading dogbane plant was recorded
immediately after fire and 4 plants were recorded the following year in a forest
supporting coniferous and hardwood species. Over the next 3 years, spreading
dogbane was absent from all sample sites [118]. Intact red pine soil blocks extracted from an unburned
site and a site burned 3 years previous were exposed to moist greenhouse conditions for 3
months. No seed or seedlings were detected in the unburned soil. The equivalent of 109,000
spreading dogbane seedlings per hectare sprouted in greenhouse samples obtained from the
burned area. No seed was found in sieved samples of burned soil, suggesting that seed had
blown in from adjacent plots postfire. Spreading dogbane frequency as measured at the burn
site was 0%, indicating poor establishment despite seed availability [4].

Montana:
Spreading dogbane was found in Rocky Mountain lodgepole pine (P. contorta
var. latifolia), Rocky Mountain Douglas-fir,
spruce (Picea spp.), and subalpine fir (Abies lasiocarpa) stands 34 years following fire in Glacier National
Park [68]. It was also detected following 2 wildfires and 1 broadcast burn in the northern Rocky
Mountains [166]. It was reported following a shelterwood cut in interior ponderosa pine-Rocky
Mountain Douglas fir forest types in Montana, on plots treated with a low-consumption burn,
high-consumption burn, or no burn. Spreading dogbane responded to increased intensity of fire
with increasing coverage [11]:

New York:
In south-central New York, spreading dogbane was found to be an overall increaser in 8
chestnut oak stands, 3 of which had experienced 1 fire, 3 that had experienced 2 fires,
and 2 that had experienced 3 fires. Average frequency on burned sites was 39.3% while on
unburned sites it was 14.3%. In a similar study conducted in 2 aspen groves, spreading
dogbane had an average frequency of 47.5% on burned sites and 0% on unburned sites [171].

South Dakota:
Spreading dogbane was detected after fire in the Black Hills of South Dakota. Vegetation
surveys took place in July or August, 2 years following a fire that consumed all organic
matter and killed all of the trees [119].

Washington:
In the ponderosa pine-Douglas-fir forest types of the Entiat Experimental Forest in the
Cascade mountains of Washington, 4 watersheds were "severely and uniformly burned"
in 1970 and received seed, seed and fertilizer, or no treatment. Spreading dogbane was most
abundant where fertilizer was applied. Refer to Tiedemann and Klock [175] for seed mix and
fertilizer types used. Average cover and frequency 1 year following treatments are shown below.
The average cover of spreading dogbane on all 4 watersheds 1, 2, 3, and 4
years after the fire was 0.9%, 1.4%, 1.1%, and 1.5%, respectively [176].

1 Year postburn

Cover (%)

Frequency (%)

Seed

0.58

46

Seed and fertilizer

1.41

73

1.06

82

No treatment

0.47

26

On a prairie site in western Washington that is burned annually as a result of military training
exercises, spreading dogbane is 1 of 16 species that retains at least 0.01% cover. Mean cover and
frequency are 0.2% and 16%, respectively [178,179]. In north-central Washington burns covered with
dense snowbrush (Ceanothus velutinus) 20 years after fire, spreading dogbane was reported to
have a "scattered" distribution [103].

Wisconsin:
Spreading dogbane is considered a prevalent species on burned jack pine stands in northwestern
Wisconsin with a frequency of 11.8% and is not considered prevalent in unburned stands. Nine control
sites and 28 burned sites averaging 3.5 burns per stand were examined. Twenty burned stands were
sampled the summer following the last spring burn while the other 8 were sampled 1 year postburn.
Spreading dogbane frequency was 6.8% greater on burned sites [186].

In the bracken fern (Pteridium aquilinum) grasslands of northeastern Wisconsin, spreading
dogbane is considered a "neutral" species, averaging 20.8% frequency on undisturbed sites
and 17.3% frequency following burning. Thirteen sites were burned once, 2 sites were burned 3 times
and 1 stand experienced 2 wildfires. Burning was done in March or April and sampling was completed
in July or August of the same year or the following year. A study utilizing 6 pairs of burned and
unburned stands of jack pine-northern pin oak (Q. ellipsoidalis) in north-central
Wisconsin reported a 1% reduction of spreading dogbane frequency on burned sites [186].

Canada: Spreading dogbane occurred on a logged, burned site in a forest
that dominated before treatment by eastern white pine and paper birch (B. papyrifera). Within
1 year of logging and 1 month of burning, spreading dogbane frequency was 5%, and aboveground biomass
totaled 0.40 g in sample plots covering a total area of 5 m2 [152]. Average ground cover
of spreading dogbane was less than 1% [153]. In another burn conducted with a gasoline-powered flamethrower
held 4 to 12 inches (10-30 cm) above the ground surface, there was no recorded effect on spreading
dogbane. Temperatures reached approximately 1700 ºF (925 ºC) [156].

Spreading dogbane in eastern Ontario was detected with 12% frequency 37 years after harvesting and
burning of a site that previously supported white spruce (Picea glauca), quaking aspen, and eastern white pine [28].
Spreading dogbane has also been reported 1 year after a prescribed burn in jack pine habitat where it
did not previously occur [109].

In the Engelmann spruce (P. engelmannii)-subalpine fir habitat type of the Selkirk Range in western Canada, spreading
dogbane was identified soon after reforestation of a burn site [148]. Following a severe fire in spruce
habitat (Picea spp.) of northern British Columbia where < 0.4 inch (1 cm) of ash and organic
matter were left behind, spreading dogbane was considered one of the most common forbs. The population
peaked after the 3rd year and had declined by year 5 [120].

The following Research Project Summary provides information on prescribed fire use and postfire response of many
plant species, including spreading dogbane:

FIRE MANAGEMENT CONSIDERATIONS:
Fire will not likely eliminate spreading dogbane. It is possible that fire may
augment populations by reducing the incidence of competing species [111].
Spreading dogbane may provide important cover on jack pine sites recently burned by
wildfire [2].

In the eastern Cascades, artificial seeding following fire resulted in reduced frequency
(P = 0.04) and cover (P < 0.001) of spreading dogbane populations [145]. Phenological
development of spreading dogbane may be altered as a result of modifications to the thermal
regime that occur postfire [52].

IMPORTANCE TO LIVESTOCK AND WILDLIFE:
Spreading dogbane is considered poisonous to domestic livestock [38,45,96,127] and is
intermittently grazed by wildlife. In Idaho's Selway Game Preserve, the leaves and flowers
of spreading dogbane account for 5% of elk diets from late June to early October [201].
Stomach content analysis of Rocky Mountain goats in the Crazy Mountains of Montana revealed
trace amounts of spreading dogbane during the fall months[142].

Palatability/nutritional value:
In central Idaho spreading dogbane has low palatability for elk and deer [159,160] and is
unpalatable to black bears [158]. It is utilized by a native slug species on the dry east slopes
of the Cascades, but is unpalatable to introduced European slugs [27]. Nutritional values of
spreading dogbane as a percentage of total dry matter are as follows [36]:

Nitrogen (%)

Ash (%)

Cellulose (%)

Lignin (%)

1.7

5.6

9.3

6.2

When spreading dogbane was treated with multi-nutrient fertilizers, concentrations of B,
Cu, K, N, and S were not significantly different (P>0.10) [184]:

B (ppm)

Cu (ppm)

K (%)

N (%)

S (%)

control

21.6

5.7

1.880

1.440

0.213

fertilized

63.1

6.9

1.890

1.580

0.333

Cover value:
Frego and Staniforth [54] maintain that spreading dogbane provides canopy cover. Species for which
this applies were not discussed.

VALUE FOR REHABILITATION OF DISTURBED SITES:
Spreading dogbane has been noted to inhabit recently disturbed sites. It was observed on a clear-cut
site in western Montana [99] and reported highest densities (83 plants per acre) 3 and 5 years following
harvest activity in California [107]. Spreading dogbane was found on a mudflow surface at Mount St. Helens
1 year following disturbance [69] and is considered an increaser along streams in southern Idaho [139],
possibly indicating a propensity to inhabit areas disturbed by flood events. Temperature measurements
conducted in southwestern Oregon in undisturbed stands indicate a preference for warm temperatures when
compared with other species [62]. In Gifford Pinchot National Forest grand fir (Abies grandis) habitat
types, spreading dogbane is used as an indicator for disturbance [177].

Spreading dogbane can be successfully transplanted. Transplanting from high elevation to low elevation sites
led to development that was delayed by 1 month when compared to plants currently at the low elevation site.
Plants moved from low elevation to high elevation sites were advanced by 1 week in 1st bloom and peak bloom
when compared to plants remaining at the low elevation site. Transplants did not produce seed at the lower
sites [53]. Spreading dogbane has been used for landscaping in residence areas that seek to utilize prairie
species [79].

Procedures for seed propagation of spreading dogbane can be found in [80].

OTHER USES:
Spreading dogbane has been used in the construction of fish nets [5] and as cordage when preferred
plants were not readily available [127]. Its use as a medicinal has resulted in sickness and death
[127].

OTHER MANAGEMENT CONSIDERATIONS:
Spreading dogbane exhibits variable responses to projects involving vegetation removal. It was
recorded on 3.4% of 2,142 sample plots in California after thinning and burning operations [132]
and was detected up to 20 years following a clearcut in western Alberta [168]. It occurred with 5%
frequency in the 2nd growing season following clearcutting and barley mulch application in Quebec
[82], and accounted for 0.001% of cover the 1st year, 0.026% the 2nd year, and 0.006% the 3rd year
following clearcutting, scarification, and planting in New Brunswick. It made up 0.006% of cover
in uncut plots during the 3rd year and was never detected in untreated clearcut plots [135]. In
the Black Hills of South Dakota and Wyoming, understory was examined after various stocking treatments
in approximately 70-year-old stands of interior ponderosa pine. Spreading dogbane production was
reported as follows [183]:

In Ontario, spreading dogbane was found 6 years after the removal of vegetation from
a peat bog and subsequent harvesting of up to 7 feet (2 m) of peat, but was not found
in bogs that had been mined 1, 10, and 24 years previously [84]. In northern
Minnesota, understory species were monitored following spring and winter full-tree
logging (tree felled and taken off-site), winter tree-length logging (tree felled,
limbed and only bole taken off site), and sites that received no treatment. Spreading
dogbane was found on the logged sites during the 2nd season following treatment. The
occurrence of spreading dogbane across treated sites was not significantly different
at the P=0.05 level [121]. Spreading dogbane cover increased from 0.5% to 0.9% following
a shelterwood cut at the Priest River Experimental Forest in northern Idaho [154]. In
the 5 years following an 8-acre clear-cut in the northern Sierra Nevada range, the
following measurements of spreading dogbane were taken [107]:

Year

% Frequency

Density (plants/acre +
standard errors)

Cover (ft²/acre +
standard errors)

Height (feet +standard
errors)

1976

2

20 + 0

10 + 0

0.2 + 0

1977

2

67 + 0

17 + 0

0.5 + 0

1978

3

83 + 150

T* + 0

0.6 + 0

1979

2

17 + 0

T + 0

0.3 + 0

1980

3

83 + 150

17 + 0

0.8 + 0

* T = trace

In a study to determine how light intensity correlates with frequency of spreading dogbane
in red pine forests, plots exposed to variable amounts of sunlight were examined. Frequency
was highest between 50% and 80% of full sunlight [151]. Spreading dogbane is not influenced
by edge effects [49]. Studies conducted to determine the change in moisture content of 21
species from early summer to mid-summer indicate that spreading dogbane was 1 of 3 species
to experience an increase [101].

In Idaho, biomass production of spreading dogbane in an area grazed primarily by cattle and
domestic sheep was greater than 3 times that in ungrazed areas. Cover and frequency were not
significantly different (P>0.05) [202].

Spreading dogbane has been successfully controlled through the use of herbicides [25,38,46,47,125,162].

71. Heinselman, Miron L. 1970. The natural role of fire in northern conifer forests. In: The role of fire in the Intermountain West: Symposium proceedings; 1970 October 27-29; Missoula, MT. Missoula, MT: Intermountain Fire Research Council: 30-41. In cooperation with: University of Montana, School of Forestry. [15735]

72. Hendrickson, William H. 1972. Perspective on fire and ecosystems in the United States. In: Fire in the environment: Symposium proceedings; 1972 May 1-5; Denver, CO. FS-276. [Washington, DC]: U.S. Department of Agriculture, Forest Service: 29-33. In cooperation with: Fire Services of Canada, Mexico, and the United States; Members of the Fire Management Study Group; North American Forestry Commission; FAO. [17276]

85. Kartesz, John T.; Meacham, Christopher A. 1999. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Available: North Carolina Botanical Garden. In cooperation with: The Nature Conservancy, Natural Resources Conservation Service, and U.S. Fish and Wildlife Service [2001, January 16]. [36715]

180. U.S. Army Corps of Engineers, Walla Walla District. 1998. Appendix table 3 - Literature review of plant species common in the Snake River region, based on several published works listed in the reference section, [Online]. In: Lower Snake River junvenile salmon migration fesibility study: Regeneration potential of vegetation on newly exposed riverside shoreline. Walla Walla, WA: U.S. Army Corps of Engineers (Producer). Available: http://www.nww.usace.army.mil/lsr/REPORTS/VEGETATION/tab3a.htm [2005, March 17]. [52739]